Research Activities, February 2011: Outcomes/Effectiveness Research: Arterial and perfusion imaging help guide treatment for stroke patients when symptom onset is unknown

Outcomes/Effectiveness Research
Arterial and perfusion imaging help guide treatment for stroke patients when symptom onset is unknown

The key to stroke recovery is knowing when symptoms first started so that therapy to restore brain blood flow can be given during the first 3 hours of symptom onset. However, a quarter of patients with ischemic stroke awaken with neurological deficits. In patients with "wake-up strokes," symptom onset is unknown. However, imaging studies that determine whether blood flow is blocked or if there is bleeding in the brain can help determine whether these patients can receive clot-busting therapy even when time of symptom onset is unknown, according to a new study.

Researchers studied 676 patients who had acute ischemic stroke. The majority (420) had strokes where the onset time was known. Another 125 patients had an indefinite time of symptom onset. The remaining 131 patients experienced wake-up strokes. All patients received computerized tomography (CT) angiography to image brain blood flow and CT perfusion (where blood flow is restored to the affected area) with intravenous or arterial tissue plasminogen activator within 24 hours of symptom onset.

The researchers found that both patients with wake-up and known-onset strokes were clinically similar. However, patients with indefinite onset strokes were found to have more severe deficits at hospital admission, more damage to the brain (larger ischemic lesions), and a worse prognosis after discharge. Patients who experienced a known-onset stroke were more frequently treated with stroke therapy (tissue plasmogen activator).

The researchers suggest revised indications for this clot-busting therapy by using image-based protocols might offer patients without a clear time of symptom onset the prospect of receiving acute stroke treatment. Their study was supported in part by the Agency for Healthcare Research and Quality (HS11392).

See "Wake-up stroke: Clinical and neuroimaging characteristics," by Gisele S. Silva, M.D., Fabricio O. Lima, M.D., Erica C.S. Camargo, M.D., and others in Cerebrovascular Diseases 29, pp. 336-342, 2010.
Research Activities, February 2011: Outcomes/Effectiveness Research: Arterial and perfusion imaging help guide treatment for stroke patients when symptom onset is unknown